The present invention relates to an array driving system for driving loads arranged like an array such as a speaker array, an LED dot matrix display, or the like, and a method of driving the loads.
As the system for driving the loads that are arranged like a one-dimensional or two-dimensional array, there are the speaker array, the LED dot matrix display, and so forth.
In the speaker array, for the purpose of the sound directivity control, etc., a number of, e.g., several hundreds of speaker units are arranged on the plane and driven.
In such speaker array, since respective speaker units must be driven by different signals, the amplifiers are needed as many as the speaker units and wirings of the twice of number of speaker units are needed between these amplifiers and the speaker units. For example, when 240 speaker units, i.e., vertical 12 columns×lateral 20 rows, are used in total, 240 amplifiers (240 ch) are needed and thus the number of wirings provided between the amplifiers and the speaker units is extremely increased.
Therefore, the speaker driving system in which the power supplying function portions are provided to an axis of abscissa and an axis of ordinate of the matrix, in which the speakers are arranged, respectively has been proposed (Patent Literature 1).
According to this proposed system, it is feasible to drive the m·n speakers of the m×n matrix by the m+n power supplying function portions.
Patent Literature 1
JP-A-2001-61196
As described above, since the speaker array of the m×n matrix is driven by the m+n power supplying function portions, the number of wirings provided to respective speaker units can be reduced and the number of power amplifiers can be reduced.
However, the currents fed from a plurality of speakers belonging to the row flow into each row wiring connected to the ground, and therefore an amount of flowing current is increased. As a result, a potential due to an impedance (ideally this impedance is 0, but actually an infinitesimal impedance is present) of the wiring is generated, and there existed the problem that the good speaker characteristic cannot be obtained. The driving circuits capable of supplying a large current to cause the speakers to suck the current thereinto are needed.
The similar situation is generated in the dot matrix display in which a plurality of LEDs are arranged like an array, or the like. In other words, when the LEDs arranged in a matrix fashion are driven, the currents fed to a plurality of LEDs that belong to each row are flown into the row wiring, so that the driving circuits capable of supplying a large current are needed.